GOG Connect is an offer from us, in collaboration with participating developers and publishers, which allows you to import certain eligible games from your steam library to your GOG account.
To use GOG Connect, you need to connect your GOG and steam accounts on the following page by logging into your steam account in the form:
Please keep in mind that you can only connect one steam account to your GOG account and that this process is permanent. If you have multiple steam accounts, please make sure you choose the correct account to connect.
The games available via GOG Connect are limited-time offers; they are not available permanently. You can always see which games are available and for how long by opening the Connect page. If you successfully import a game, a copy of it will be added to your library on GOG.com where it will be available for download.
You can find more information about GOG Connect in this FAQ.